Some theropods, like many carnivores, were indeed cannibals. The best evidence so far is from Carnotaurus sastrei’s close cousin Majungasaurus crenatissimus, from the Late Cretaceous of Madagascar. A specimen of bone reveals bite marks consistent with having been created by another M. crenatissimus (Rogers et al. 2003). (No other theropods as large are known from the same formation.)

If you skipped ahead and looked at the references, you noticed that Rogers et al. mention Majungatholus atopus in the title, not Majungasaurus crenatissimus. These two binomials were named for different specimens, M. crenatissimus for a partial theropod mandible and M. atopus for some thick skull parts that were originally thought to be pachycephalosaurian (hence the generic name, meaning “Majunga dome [head]”). But material uncovered in the 1990s showed that the thick-headed beast was, in fact, a carnotaurine theropod. Further research shows it to be indistinguishable from (and hence probably synonymous with) M. crenatissimus.

Speaking of pachycephalosaurs, a very cool-looking one was just named, and the name should please a lot of young readers (and some old): Dracorex hogwartsia Bakker et al. 2006, the “Hogwarts dragon king”, named after fictional character Harry Potter’s wizardry school. High-resolution pictures of the skull can be seen here. (To those groaning at Bakker et al.’s name for the creature—hey, it’s better than Bambiraptor.)

The specimen is housed at the Indianapolis Children’s Museum, a far better place for young ones than a Carnotaurus nest…